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Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential

Background

Cardiac ultrasound is frequently used in the emergency department (ED) to effectively identify  pericardial effusion, differentiate causes of shock, assess left ventricular function, and guide cardiopulmonary resuscitation (CPR). However, cardiac ultrasound employed in the ED is usually transthoracic echocardiography (TTE) as opposed to transesophageal echocardiography (TEE). TTE can often be limited, especially in critically ill patients and patients with high BMI. TEE offers the ability to reliably obtain continuous high-quality images that can be performed without interrupting CPR. Despite this, TEE is not often employed in the ED due to a variety of factors, including transducer cost, invasiveness, physician training, and hospital culture.

Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential: Observational Results from a Novel Ultrasound Program

 

Clinical Question

Is TEE performed by emergency medicine trained  physicians, in the emergency department setting, feasible and does it provide clinical utility?

Methods & Study Design

  • Design
    • Retrospective Review
  • Population
    • Study performed during a TEE in the ED pilot program by an academic emergency medicine program comprising 2 separate EDs, one of which is a regional trauma center.
    • All patients who underwent TEE in the ED during the 2-year program period were included.
  • Exclusion criteria
    • None
  • Intervention
    • TEE was performed on critically ill, intubated patients. Most commonly, the mid-esophageal 4-chamber view, followed by the transgastric short axis, mid-esophageal long axis, and bicaval views  were obtained.
  • OutcomesThe clinical impact of TEE, divided into two categories:
      • Diagnostic influence on clinical decision making
      • Therapeutic influence on procedures, medications, fluids, and CPR

Results

    • 54 TEE exams performed with 100% probe insertion success rate
      • 83% on first attempt
      • 11% required multiple attempts
      • 6% required use of a laryngoscope
      • 98% of exams produced images that were interpretable by the operator
    • TEE was diagnostically influential in 78% of cases
      • Excluded cardiac cause of arrest (56%)
      • Identified depressed left ventricular function (15%)
      • Identified hypovolemia (13%)
      • Identified regional wall motion abnormalities (6%)
      • Identified aortic dissection (4%)
    • TEE was therapeutically influential in 67% of cases
      • Influenced changes to CPR (43%)
      • Directed cessation of resuscitation (30%)
      • Guided hemodynamic support (26%)
    • No major adverse effects from probe placement identified

Strengths & Limitations

  • Strengths
    • TEE exams were performed successfully by 14 different emergency physicians at 2 separate sites after only 4 hours of training, which demonstrated well the feasibility of TEE use in the ED on a more widespread basis.
    • Well-described outcomes
  • Limitations
    • Retrospective
    • Relatively small sample size
    • No comparison with TTE

Author's Conclusions

“ED- based TEE showed a high degree of feasibility (98% determinate rate) and clinical utility, with a diagnostic and therapeutic influence seen in the majority of cases. Focused TEE demonstrates the most promise in patients who are intubated and have either undifferentiated shock or cardiac arrest.”

Our Conclusions

This study demonstrates that performing TEE in the ED is both feasible and safe, and can be implemented with limited training of the physician staff. It also shows that TEE does have some clinical utility in the ED, specifically the detection of aortic dissection. However, the most common therapeutic effect noted in the study was the assessment of CPR quality, which can typically be assessed with less invasive means such as femoral pulse palpation and waveform capnography. The other common findings noted in the study (i.e. depressed ejection fraction, hypovolemia, guidance of hemodynamic support) can typically be assessed with more traditional and less invasive TTE. In order to truly evaluate the utility of TEE in the ED, a prospective study showing a comparison of TEE with TTE, and other less invasive diagnostic modalities, would need to be performed. That being said, having the ability to diagnose aortic dissection at the bedside and to guide resuscitation via direct cardiac visualization during ongoing CPR are important considerations. This is a promising pilot study that opens up the door for further research evaluating the utility of TEE in the ED, however at this point, it is not clear whether it will perform better than traditional TTE and other clinical adjuncts in both diagnostic and therapeutic abilities.

The Bottom Line

Performing TEE in the ED is both feasible and safe, and does provide useful clinical information. However more studies are required in order to assess the true clinical utility of this modality.

Authors

This post was written by Toby Matt, MS4 at UCSD. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Arntfield R, e. (2017). Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential: Observational Results from a Novel Ultraso... - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 30 October 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26508495
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